Welcome to GMTC! I searched ebay for that kit because I was curious. When I worked in the garage I saw a kit that was pretty cool. Basically, you removed the handle for the windows. Then you fit this 2" x 2" box onto the exposed splines in the window shaft. You ran some wires to it, and drove a screw thru a spot to stop it from spinning. It was all self contained. The switch was on the box, the motor inside. It looked a little funny but, I was pretty impressed. I have never seen that kit again.